Stress is commonly used to describe the detrimental effectsof a variety of conditions surrounding animals on their health performance. Environmental stress causes an increasein oxidative stress and an imbalance in antioxidant status. Oxidative damage increases in stressed poultry when the plasma antioxidant vitamins and minerals such as vitamin C, E, folic acid, and zinclevels declined. Stress factors in birds involve many elements of the transport processes which may be detrimental to the birds. These factors include alteration in atmospheric temperature, poor handlingby man, removal of feed and water (starvation), high ambient temperature (AT) and relative humidity (RH). Other factors incude vaccination, disease conditions such as coccidiosis, novelty,confinement, motion, noise, microthermal core within the vehicle and the use of inappropriate vehicles. Live birds of all ages are being transported mainly by roads to their various destinations and across different ecological zones throughout the year. Mortality increaseswith journey length. The adverse effects of these factors and their combinations may range from mild discomfort and aversion to death. This review was aimed at providing comprehensive information on the role of vitamin C in combating stress factors in poultry with the view of exploring its potentials for future research undertaking.Information compiled in this review were obtained from search engines such as Elsevier, Pubmed, Springer, Medline, Science Direct, Google Scholar, and a library search for articles published in peerreviewedjournals. 100 to 200 mg/kg feed of vitamin C is capable of converting stress factors in poultry and thereby improving the productivity.

The objective of this study was to evaluate the ability of a long-term antioxidant-supplemented diet to regulate the oxidative stress and general health status of dogs involved in animal-assisted intervention (AAI) programs. Oxidative stress is a consequence of the accumulation of reactive oxygen species (ROS). Exercise-induced oxidative stress can increase muscle fatigue and fiber damage and eventually leads to impairment of the immune system. A randomized, placebo-controlled, crossover clinical evaluation was conducted with 11 healthy therapy dogs: 6 females and 5 males of different breeds and with a mean age of 2.7 ± 0.8 y (mean ± SEM). The dogs were divided into 2 groups, 1 fed a high quality commercial diet without antioxidants (CD) and the other a high quality commercial diet supplemented with antioxidants (SD) for 18 wk. After the first 18 wk, metabolic parameters, reactive oxygen metabolite-derivatives (d-ROMs), and biological antioxidant potential (BAP) levels were monitored and showed a significant reduction of d-ROMs, triglycerides, and creatinine values in the SD group (P < 0.05) and a significant increase in amylase values in the CD group (P < 0.01). At the end of this period, groups were crossed over and fed for another 18 wk. A significant decrease in amylase and glutamate pyruvate transaminase (GPT) values was observed in the CD and SD group, respectively (P < 0.05). In conclusion, a controlled, balanced antioxidant diet may be a valid approach to restoring good cell metabolism and neutralizing excess free radicals in therapy dogs.

Both pregnancy and obesity can influence significant changes in the immune system. On this basis, the present study proposes to evaluate the humoral immune response of overweight pregnant mares in response to a commercial vaccine. Thirty pregnant Crioulo mares were separated according to body condition score (BCS) into overweight (BCS≥7/9) or lean-control (BCS= 5-6/9). In each group, the animals were subdivided into vaccinated and controls. The mares were vaccinated against EHV-1 in two doses spaced 21 days apart and had their blood collected monthly, for five months, for antibody evaluation. Both vaccinated groups had an increase in specific neutralizing antibodies after the vaccine. However, after the second dose, there was no increase in antibodies in any of the groups. Vaccinated overweight and lean-control mares did not differ at any time point. Therefore, this study demonstrated that obesity does not influence the humoral immune response in pregnant Crioulo mares.